Temperature displaying fan

ABSTRACT

An electric fan assembly has a rotating fan blade mounted with an array of light emitting devices; a thermistor mounted on the fan blade and providing an analog signal corresponding to a sensed temperature, a fan blade position synchronizing switch and a microcontroller and display driver having an analog to digital converter. The microcontroller and display driver is connected to receive the signals from the thermistor and synchronizing switch and programmed to selectively power the light emitting devices when the fan blade is in a synchronized position to provide an alpha numeric display of the ambient temperature by a persistence-of-vision effect.

RELATED APPLICATIONS

Priority is claimed from application No. 60/759,184 filed Jan. 13, 2006, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a rotary electric fan assembly that senses the ambient temperature and displays the ambient temperature by the persistence-of-vision effect.

BACKGROUND OF THE INVENTION

There are numerous devices of the prior art, including electric fan assemblies, that provide rotating LED arrays to produce images displaying information/data by the persistence-of-vision or after-image effect.

For example, US 2002/0135541 published Sep. 26, 2002, issued as U.S. Pat. No. 6,856,303 to Kowalewski teaches a rotating display system in which a series of individually powered LED's are swept in a cylindrical plane to display externally generated text and graphics, including, possibly, stock quotes; and, U.S. Pat. No. 6,037,876 issued March 2000 to Crouch teaches a lighted message fan assembly having a row of individually powered, fan blade mounted light sources for displaying internally generated or externally communicated images. The disclosures of the above two publications are incorporated herein by reference.

However, none of the prior art teaches a rotary electric fan assembly which both senses the ambient temperature and displays the sensed temperature by a persistence-of-vision effect, or senses and displays any other ambient environmental state, by a persistence-of-vision effect.

SUMMARY OF THE INVENTION

An object of the invention is to provide a rotary electric fan assembly which both senses the ambient temperature and displays the ambient temperature by the persistence-of-vision effect.

An additional object of the invention is to provide such fan assembly which senses the temperature of the air as it actually passes through the fan blade assembly.

A further object of the invention is to provide such fan wherein a temperature sensor is mounted on the fan blade, remote from parts of the fan assembly subject to heating by the fan mechanism so that the temperature of the ambient air is measured accurately.

According to one aspect, the invention provides an electric fan assembly of a type having a rotating fan blade mounted with an array of light emitting devices; a data supply, a fan blade position synchronizing switch and, a microcontroller and display driver for selectively powering the light emitting devices when the fan blade is in a synchronized position for displaying the data by a persistence-of-vision effect, wherein the data is supplied by a temperature sensor mounted on a portion of the electric fan assembly remote from a heat generating region thereof so that the ambient air temperature is displayed in an area swept by the fan blade during rotation.

The resulting fan display is both amusing and informative to users in displaying the ambient environmental air temperature.

As temperature is an analog quantity, an analog to digital converter is in practice necessary to provide digital signals to drive the LED array. Such analog to digital converter may be provided as a separate unit, combined as a package with the temperature sensor itself, or combined as a package with the microcontroller.

The temperature sensor may be mounted on the fan blade assembly, preferably on the fan blade, so that the temperature of ambient air will be sensed while passing through the fan blade assembly permitting an extremely accurate result corresponding to the temperature of the air steam actually being blown towards the user.

It is further preferred that the LED array, the microcontroller and display driver; and the temperature sensor are mounted on a common circuit board attached to a common fan blade.

This provides a compact structure which can be assembled by conventional mass production techniques enabling economic high volume production.

It is additionally preferred that the synchronizing means comprises a phototransistor mounted on the common circuit board on the fan blade and aligned for momentary registration with a LED mounted in the fan housing during each rotation of the fan blade assembly to provide the synchronizing signal.

This enables all three active elements to be assembled with the fan blade as a single unit.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be readily understood a specific embodiment thereof will now be described by way of example only with reference to the accompanying drawings in which:

FIG. 1 is a schematic perspective view of a temperature sensing and displaying fan according to the invention with the fan guard omitted for clarity;

FIG. 2 is a schematic cross-sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a schematic front elevation of the fan in operation displaying a sensed temperature;

FIG. 4 is a block diagram showing the main elements of the temperature sensing and displaying circuit of the fan;

FIG. 5 is a circuit diagram of the power supplying elements shown in FIG. 4; and,

FIG. 6 is a circuit diagram of the temperature sensing and displaying element shown in FIG. 4.

PARTICULAR DESCRIPTION

As shown in FIG. 1-3, the temperature sensing and displaying fan 1 comprises a pedestal base 2 supporting a housing 3 for a fan motor 4 having a stator winding 5 surrounding a rotor winding 6 fixed on one end of drive shaft 7. The other end of the drive shaft protrudes out from the motor housing 3 and is fixed to hub 8 which is molded in one piece with fan blades 9 to form fan blade assembly 10. The drive shaft 7 also carries a secondary winding 11 of a 1:1 rotary transformer 12.

A circuit board mounted rectifier/filter and high frequency inverter unit 13 is mounted in the motor housing 3 and has a low voltage power input tap 14 from the motor stator winding 5 and power output leads 15 and 17, respectively, connected to an infra-red LED 16 of a synchronizing switch on a front of the motor housing 3, behind the fan blades, and to the primary winding 18 of the rotary transformer 12, respectively.

A circuit board mounted rectifier/filter and voltage regulator unit 19 is fixed in a rear cavity 20 in the hub 8. An IR phototransistor 22, microcontroller 23 and thermistor 24 are mounted on the display circuit board 25 and a single row LED array 27 is mounted displaced therefrom on a front face. The circuit board is fastened to the rear face of one of the fan blades so that the LED array 27 is aligned with a radially extending window 27 in the blade and the phototransistor is radially aligned with the LED 16 for momentary switching registration therewith during each rotation of the fan blade to provide the synchronization switch.

Mains power is supplied to the motor via power cord 29 by operation of power switch 30 mounted on the motor housing 3 so that the LED array is lit during each blade rotation to display a numerical indication 31 of ambient temperature sensed by the thermistor 24 at the top of the swept area and the unit of measurement 32 at the bottom, as shown in FIG. 3.

In summary, as shown in FIG. 4, the main circuit elements comprise a rectifier/filter and high frequency inverter 13 connected to a winding to tap at reduced voltage from the stator of fan motor 4. The high frequency inverter 13 provides a low voltage dc to the IR LED 16 and a high frequency square wave (e.g 18 KHz) to the primary 18 of the rotary transformer 12. The rectifier/filter and voltage regulator 19 is connected to the transformer secondary 11 to receive the high frequency square wave induced therein and to provide a rectified and regulated dc output to power thermistor 24, photo transistor 22, the microcontroller/analog to digital converter/display driver 23 and the LED array 26.

As shown in detail in FIG. 5, a rectifying stage 35 of the rectifier/filter and high frequency inverter 13 is constituted by a set of rectifying diodes D21-D24 in parallel with filter capacitor C21 connected to provide a smoothed low voltage dc to IR LED D25 (16), biased by resistor R21, for continuous operation and to the high frequency inverter stage 36 comprising IC U21, (part TL494 manufactured by Texas instruments of Dallas Tex. with the pulse width modulating facility inoperative). Resistors R22 and C22 determine the oscillating frequency. IC U21 is connected to drive a push-pull H-bridge in which pairs of transistors Q21,Q24 and Q22, Q23 are respectively driven alternately by IC ports C1,E1 and C2, E2 to provide a square wave to the primary 18 of the rotary transformer 12. Diodes D26-D29 clamp high voltage transients that develop across the primary 18 of rotary transformer 12.

In rectifier/filter and voltage regulator 19, the square wave induced in the secondary 11 is rectified and smoothed by a set of rectifying diodes D11-D14 in parallel with smoothing filter capacitor C11 and output to voltage regulator U11, (part LM317 manufactured by National Semiconductor of Santa Clara, Calif.). Resistors R11 and R12 set up the correct regulatory response of the voltage regulator. The output from voltage regulator U11 in conjunction with transient response improving capacitor C12, supplies low voltage dc (e.g 3 v) for operation of the thermistor 24, phototransistor 22 of the synchronization switch, the microcontroller, analog to digital converter and display driver 23 and, to the LED array 26, shown in FIG. 6.

The microcontroller, analog to digital converter, and display driver 23 (U1) are parts of a C8051F334 manufactured by Silicon Laboratories of Austin, Tex. C2CK and C2D are program loading inputs to respective ports Rst/C2CK and P2.0/C2D of the microcontroller. Capacitor C1 holds the microprocessor in reset mode initially when turned on, until fully operational. The thermistor 24 provides an analog voltage signal corresponding to the sensed ambient temperature which is sampled by the analog to digital converter of the microcontroller via port PO.3 and is converted to a digital signal which selectively lights the arrayed LEDs D1-D12 (26) at intervals during each rotation of the fan blade in accordance with the rotational position as determined by the programming of the microcontroller, synchronism being provided by signals from the switching phototransistor 22 connected to port PO.1. C2 is a by-pass capacitor.

Although synchronization is obtained by a LED and phototransistor combination, other types of synchronizing switches utilizing magnetic means such as reed switches and other electromagnet devices or optical devices may be used.

The low voltage ac could be provided by a transformer instead of from the motor winding tap 

1. A rotary electric fan assembly for sensing and displaying ambient environmental temperature by a persistence-of-vision effect comprising: a housing; an electric motor mounted in said housing; means for connection to a power supply; a fan blade assembly connected for rotation by the motor; a temperature sensor mounted on the fan blade assembly for providing an analog electrical output signal corresponding to a temperature sensed; an LED array mounted on a fan blade so as to be swept by fan blade rotation through an area in view of a spectator; synchronizing means for providing a synchronizing signal indicating a rotational position of the fan blade assembly; means for receiving the analog electrical output signal from the temperature sensor and for converting the analog signal to a corresponding digital output signal; and, a microcontroller and display driver connected to receive the digital output signal and the synchronizing signal and for providing a output selectively lighting LEDs of the array in accordance with the sensed temperature and rotational position of the fan blade assembly, so that the temperature of ambient air will be sensed and displayed in the area swept by the fan blade by the persistence-of-vision effect.
 2. A rotary electric fan assembly according to claim 1 wherein the means for receiving the analog electrical output signal from the temperature sensor and for converting the analog signal to a corresponding digital output signal is combined as a package with the microcontroller.
 3. A rotary electric fan assembly according to claim 1 wherein the temperature sensor is mounted on a fan blade of the fan blade assembly so that the temperature of ambient air will be sensed while passing through the fan blade assembly.
 4. A rotary electric fan assembly according to claim 3 wherein the LED array, the microcontroller and display driver; and the temperature sensor are mounted on a common circuit board attached to a common fan blade.
 5. A rotary electric fan assembly according to claim 4 wherein the synchronizing means comprises a phototransistor mounted on the common circuit board and a LED mounted on the housing and aligned for momentary registration with each other during each rotation of the fan blade assembly to provide the synchronizing signal.
 6. A rotary electric fan assembly for sensing and displaying ambient environmental temperature by a persistence-of-vision effect comprising: a housing; an electric motor mounted in said housing; means for connection to a power supply; a fan blade assembly connected for rotation by the motor; a temperature sensor mounted on a portion of the fan assembly at a location remote from a heat generating region for providing an analog electrical output signal corresponding to a sensed temperature; an LED array mounted on the a fan blade so as to be swept through an area in view of a spectator by fan blade rotation; synchronizing means for providing a signal indicating a rotational position of the fan blade assembly; an analog to digital converter for converting the analog electric output signal from the temperature sensor into a corresponding digital output signal, and, a microcontroller and display driver connected to receive the signals from the analog to digital converter and the synchronizing means and programmed to provide a output signal to selectively light LEDs of the array in accordance with the sensed temperature and rotational position of the fan blade assembly, so that the temperature of ambient air will be sensed and displayed in the area through which the LED array rotates by the persistence-of-vision effect.
 7. A rotary electric fan assembly according to claim 1 wherein the analog to digital converter is combined as a package with the microcontroller.
 8. A rotary electric fan assembly for displaying information/data by a persistence-of-vision effect of a type comprising: a housing; an electric motor mounted in said housing; means for connection to a power supply; a fan blade assembly mounted for rotation by the motor; an LED array mounted on the fan blade so as to be swept through an area in view of a spectator by fan blade rotation; synchronizing means for providing a signal indicating a rotational position of the fan blade assembly; a microcontroller and display driver connected to LEDs of the array and supplied with data to be displayed and programmed to provide a digital output to selectively light LEDs in conjunction with signals from the synchronizing means to display the supplied data by the persistence-of-vision effect, the improvement residing in that means for supplying display data to the microcontroller and display driver comprises a temperature sensor provided on a portion of the fan assembly remote from a heat generating region thereof so that the data displayed corresponds to the ambient temperature sensed by the temperature sensor.
 9. A rotary electric fan assembly according to claim 7 wherein data supplied by the temperature sensor is in analog form and the microcontroller and display driver includes an analog to digital converter.
 10. An electric fan assembly for displaying information/data by a persistence-of-vision effect of a type having a rotating fan blade mounted with an array of light emitting devices; a data supply; a fan blade position synchronizing switch; and, a microcontroller and display driver connected to the data supply and to the synchronizing switch so as to selectively power the light emitting devices to display the data in an area swept by the fan blade during rotation by a persistence-of-vision effect, wherein the data is supplied by a temperature sensor mounted on a portion of the electric fan assembly remote from a heat generating region thereof so that the ambient air temperature is displayed. 